1. Technical Field
The subject invention relates to a flexible endless conveyor belt having a fold-over capability for conveying relatively-loose bulk material from one point to another especially along steep inclines and declines, the belt cover-flaps completely enclosing the load while it is conveyed.
2. Background Information
The subject invention which relates to an endless folding belt adapted for use in belt conveyor systems provides a significant improvement in such systems wherein the belt has a substantially longer service life at its hinged areas.
The belt is adapted for use in conveyor systems to move the folding belt by drive rolls while supported in intermediate areas on idler rolls, the belt having a pair of continuous flexible longitudinal cover or hinge flaps which permit the flaps to be folded and unfolded to facilitate loading and unloading of the belt at several load handling stations or positions. The folding belt is normally folded to enclose bulk materials during their transport from one position to another to eliminate spillage of the load or its contamination during transport and to permit the load to move along steep inclines and declines. The folding belt is capable of carrying significantly greater loads without producing dust-emitting conditions in the vicinity of the belt, the belt having an improved construction in its hinged areas for much longer-service life.
Prior forms of such folding belts have heretofore utilized single grooves at their hinged areas which place a much more severe bending moment on the belt in obtaining a hinged effect wherein the belt is essentially folded on itself at the pair of similarly singly grooved areas. Where the belt is formed from flexible elastomeric material, the single grooves are stretched in a severe deleterious manner which shortens belt life where the belts are employed to carry significantly greater volumes of bulk material between loading and unloading positions. Belts having such single grooves at the hinged areas are disclosed in U.S. Pat. No. 4,709,806 along with known types of conveyor systems for transport of loose materials in an enclosed manner. While the singly-grooved hinged areas have been used previously the amount of undue stress placed on the belt at the twin hinged areas causes excessive wear thereat shortening belt life and requiring increased maintenance.
Prior to the advent of fold-over belts, open belts have been used previously in the art to convey bulk materials in a manner open to the atmosphere. In view of inherent dusting problems, the industry has utilized metal shrouding or other forms of enclosure of the belt to eliminate contamination dusting and to maintain the conveyed material in an essentially clean and uncontaminated condition. The use of shrouding occasionally results in accumulation of dust and in some cases a creation of explosive mixtures which occurrences are particularly dangerous and to be avoided. Prior to the use of folding-belt conveyor systems, such systems were objectionable in allowing spillage of the conveyed material frequently due to belt construction and its mounting for continuous movement. There has been a need in the art for an improved fold-over belt structure having much longer service life which requires lesser maintenance and downtime due to belt failure or weaknesses requiring costly belt replacement.
Furthermore, since fold-over belts can go up steep angles due to the pressure of the top flaps trapping material against the bottom carrying side of the belt, it is mandatory that the belt have a controlled cross section so that the material will not slide back along the belt in steep angles. Therefore, it is necessary to close the top flaps as much as possible to match the cross sectional area of the belt to the material being carried thereby.